Here's the caveat for the DIY-ers.
You never know what you'll find underneath.

What looks perfectly fine on the surface can be a nightmare underneath. Case in point: Windows should be nailed into the the framing, right? Not at our house. The cheap-*** contractor who built our place used liquid nails for a lot of stuff, including the windows. So, no nails to take out. The problem is that liquid nails works so well that we couldn't use normal methods ( even a crow bar) to remove the old windows. What we ended up having to do what break the glass out of each window frame, and THEN use the crowbar to pry the aluminum window frame off the wooden framing one side of the rectangle at a time. Talk about a pain....We find fun stuff like this all the time; we end up redo a whole lot of stuff that was just done plain wrong or uber-cheap.